Construction

ABSTRACT

Apparatus is disclosed for use in construction. The apparatus comprises a base unit adapted to be fixed to a structure in an elevated position relative to the ground, and a mechanism for moving a construction worker and/or construction material relative to the base unit.

This application claims the benefit of United Kingdom Patent ApplicationNo. 0500619.2, filed Jan. 13, 2005, which is hereby incorporated byreference in its entirety.

FIELD OF THE INVENTION

This invention relates to construction, and in particular to theconstruction of tall buildings, such as skyscrapers, using apparatushaving means for moving construction workers and/or constructionmaterial relative to the structure.

BACKGROUND

Modern buildings, whether commercial, office or residential units, areoften constructed by first forming a building framework on suitablefoundations, and then forming the floors and walls of the buildingwithin and about the building framework. The building frameworkgenerally comprises a plurality of vertically orientated steel columnsto which horizontally orientated steel beams or girders are attached toform a floor-supporting framework for each floor of the building.

Once the foundations have been formed and the vertical columns erected,the floor-supporting frameworks are constructed about, and fixed to, thevertical columns. Beams are raised to the level of a particular floor ina horizontal orientation and fixed by construction workers toappropriate vertical columns or other horizontal beams until thefloor-supporting framework for that floor is completed. Once afloor-supporting framework has been constructed, a floor is formedabout, or on, the supporting framework. For example, concrete istypically cast about each floor-supporting framework, thereby formingthe floors of the building.

The horizontal beams are typically raised to their intended fixing siteusing a tower crane or the like. The construction workers who fix thehorizontal beams to the building framework are conventionally raised tothe fixing site using a Mobile Elevated Work Platform (MEWP) that issituated on the ground. However, a MEWP situated on the ground is onlysuitable for constructing the first few floors of a building due to itslimited vertical and horizontal range, and is therefore unsuitable forthe construction of tall buildings and for use at construction siteshaving limited space or unsuitable ground conditions. In this case,construction workers are either transported to the fixing site on a workplatform carried by a crane, or a MEWP is lifted onto the highestcompleted floor by a crane and then used to transport constructionworkers to fixing sites within range of the MEWP.

The method of lifting a MEWP onto the highest completed floor using acrane, and then using the MEWP to transport construction workers tofixing sites within range of the MEWP, suffers from numerousdisadvantages. Such disadvantages include the need to install floorsbefore the building framework is completed in order to support the MEWP.In particular, the loading of a concrete floor should not occur untilthe concrete has cured to about 75% of its full loading capacity, whichgenerally takes at least five days following installation, and concretefloors typically need at least twenty-eight days to cure fully. Inaddition, there is an increased risk of an accident occurring when aMEWP is supported on the floor of a partially constructed buildingrather than the ground. In particular, the drive system of a MEWP isgenerally not disabled at a construction site, and hence aninexperienced operator could drive the MEWP over the edge of the floorbecause guardrails are generally designed to prevent constructionworkers, rather than heavy machines, from falling over the edge.

The method of transporting construction personnel to the fixing site ona work platform carried by a crane also suffers from disadvantages,which include the increased risk of an accident occurring whenconstruction workers are left, secured by a harness to the buildingframework, at the fixing site whilst the crane raises a beam to thefixing site.

Whatever method is used to bring the construction workers into position,it is commonly the case that the workers need to access open steelwork.

This may involve straddling the steelwork, climbing ladders lashed tothe steelwork and the workers securing themselves to the steelwork usinglanyards and safety harnesses. Considerable hazards are involved in suchoperations.

In general, the inefficiency and/or inconvenience of conventionalmethods used in the erection of structural frameworks for buildings mayincrease the likelihood of non-compliance with safety regulations andproper working procedures, with an increased risk of harm to theconstruction personnel.

There has now been devised an improved apparatus which overcomes orsubstantially mitigates the above-mentioned and/or other disadvantagesassociated with the prior art.

SUMMARY

According to a first aspect of the invention, there is providedapparatus for use in construction, which apparatus comprises a base unitadapted to be releasably fixed to a structure in an elevated positionrelative to the ground, and a mechanism for moving a construction workerand/or construction material relative to the structure.

According to a further aspect of the invention, there is provided amethod of construction comprising the steps of

(a) providing apparatus as described above;

(b) raising the apparatus relative to a structure;

(c) releasably fixing the apparatus to the structure in an elevatedlocation relative to the ground; and

(d) moving a construction worker and/or construction material relativeto the structure.

The apparatus and method according to the invention are advantageousprincipally because the apparatus is releasably fixed to a structure, inan elevated position relative to the ground, before being used to move aconstruction worker and/or construction material relative to thestructure. The apparatus and method according to the invention aretherefore safer than prior art apparatus and methods in which theapparatus is simply placed upon either the ground or a concrete floor ofthe structure, and then used to move construction workers and/orconstruction material relative to the structure. The risk of accidentsoccurring whilst moving construction workers and/or constructionmaterial relative to the structure is therefore significantly reduced bythe present invention.

The base unit is preferably adapted to accommodate a constructionworker. Most preferably, the base unit is adapted to accommodate aconstruction worker whilst the apparatus is raised relative to thestructure. In particular, the base unit preferably satisfies recognizedsafety standards relating to transportation platforms for constructionworkers, which are commonly referred to in the UK as “man-riders”. Thebase unit preferably comprises a floor and a peripheral barrier, mostcommonly in the form of a safety rail. The construction workeraccommodated by the base unit is preferably attached to the safety railby a safety harness during the raising of the apparatus relative to thestructure.

The apparatus may be raised relative to the structure by a crane. Theapparatus is then preferably fixed to the structure in an elevatedlocation relative to the ground while the crane remains engaged with theapparatus. The crane then preferably disengages from the apparatus. Inthis case, the apparatus is preferably adapted to be coupled to a crane,by means of attachment lugs, for example.

Alternatively, the apparatus may include a mechanism for raising itselfrelative to the structure. For instance, the apparatus may include araising mechanism that cooperates with horizontal and/or vertical beamsof the structure to raise the apparatus relative to the structure. Mostpreferably, operation of the raising mechanism is controllable by aconstruction worker accommodated by the base unit. The raising mechanismmay also be adapted for fixing the base unit to the structure in anelevated position relative to the ground.

The apparatus according to the invention preferably comprises amechanism for moving a construction worker relative to the base unitand/or a mechanism for moving construction material relative to the baseunit. The mechanism for moving construction material relative to thebase unit may comprise a crane or a winch, for example.

The mechanism for moving a construction worker relative to the base unitpreferably includes a work platform that is adapted for accommodating aconstruction worker, and a mechanism for moving the work platformrelative to the base unit. In use, the work platform and constructionworker are preferably elevated to a fixing site of greater elevationthan the base unit relative to the ground, at which site theconstruction worker fixes construction material to the structure. Mostpreferably, construction material is transported to the constructionworker at the fixing site by a crane.

In presently preferred embodiments, the apparatus according to theinvention comprises a support body mounted on the base unit, and a boomextending between the support body and the work platform. Mostpreferably, the apparatus has the general form of a conventional MobileElevated Work Platform (MEWP) but including anchorages for fixing thebase unit to a structure such that the base unit is in an elevatedposition relative to the ground, said anchorages preferably beingmovably mounted relative to the base unit. Therefore, unlike aconventional MEWP, the apparatus according to the invention does notrequire any ground drive or support system.

Preferably, the support body is rotatably mounted on the base unit. Theboom is preferably pivotally mounted at one end to the support body, andat the other end to the work platform. The apparatus preferably includesa mechanism, such as a first hydraulic ram, for rotating the boomrelative to the support body about a single horizontal axis. Similarly,the apparatus preferably includes a mechanism, such as a secondhydraulic ram, for rotating the work platform relative to the boom abouta single horizontal axis.

The apparatus preferably includes a self-levelling system that maintainsthe work platform in a generally horizontal orientation. Any suitableself-levelling system may be used. For instance, the self-levellingsystem may be controlled by a microprocessor, such that the systemeither continuously or intermittently senses the orientation of the workplatform, and automatically maintains the work platform in a horizontalorientation during use.

Most preferably, the boom is telescopically extendible and retractable.In this case, the boom will generally comprise a plurality of tubularmembers that are slidably engaged with one another. Alternatively,however, the boom may be of fixed length.

In addition, the apparatus preferably includes a mechanism for rotatingthe work platform relative to the boom about at least one generallyvertical axis. Most preferably, the apparatus includes at least oneconnecting member that couples the boom and the work platform together.The connecting member is preferably pivotally connected to the boom atone end, and pivotally connected to the work platform at the other end.Most preferably, the apparatus includes a mechanism for rotating theconnecting member relative to the boom about a first vertical axis, anda mechanism for rotating the work platform relative to the connectingmember about a second vertical axis, such that the work platform ismoved within a generally horizontal plane relative to the boom. Such anarrangement allows the work platform to be manoeuvred around obstaclessuch as vertical beams.

The work platform may be adapted to accommodate one or more constructionworkers, and preferably comprises a floor and a peripheral safety rail.The hydraulic rams, the telescopic boom, and/or the rotatable supportbody that determine the position of the work platform relative to thebase unit are preferably controllable by the construction workeraccommodated by the work platform. Most preferably, a control panel ismounted to the work platform to enable the construction worker to movethe work platform relative to the base unit, and hence control actuationof the hydraulic rams, the telescopic boom, and/or the rotatable supportbody that determine the position of the work platform relative to thebase unit. The control panel on the base unit preferably includes aselector switch that must be in an appropriate state for the controlpanel on the work platform to function.

Most preferably, the apparatus comprises a plurality of anchorages forfixing the base unit to a structure such that the base unit is in anelevated position relative to the ground. Preferably, one or more ofsaid anchorages, and most preferably all of said anchorages, are movablymounted relative to the base unit. This enables the base unit to befixed readily to a range of different structures.

Preferably, the apparatus according to the invention comprises three ormore anchorages for fixing the base unit at three or more points to thestructure, the three or more anchorages being movably mounted relativeto the base unit. Most preferably, the apparatus according to theinvention comprises four anchorages for fixing the base unit at fourpoints to the structure, the four anchorages being movably mountedrelative to the base unit.

The anchorages of the apparatus are preferably adapted to engage one ormore beams or the like of the structure. These beams will generally takethe form of I-section beams that are conventionally formed from steel.However, the anchorages may be adapted to engage different beamprofiles, such as beams having circular, rectangular or hexagonalcross-sectional shapes. Most preferably, the anchorages of the apparatusare adapted to engage a pair of horizontal beams that are orientatedparallel to each other. However, the anchorages may be adapted to engageother arrangements of beams, such as arrangements comprisingnon-parallel horizontal beams and/or vertical beams.

Each anchorage is preferably attached to a leg that extends from thebase unit. Each anchorage is movable relative to the base unit, and suchmovement is preferably brought about by movement of the leg relative tothe base unit. In particular, each leg is preferably movable relative tothe base unit and/or adjustable in length such that the length of thatpart of the leg that projects beyond the base unit is alterable. Mostpreferably, the apparatus comprises four legs with an anchorage attachedto the distal end of each leg.

Each leg may be rotatably mounted to the base unit. In this case, eachleg is preferably also telescopically extendible and retractable. In apresently preferred embodiment, however, each leg is slidably mountedwithin a housing that is fixed relative to the base unit, such that ananchorage at one end of each leg may be extended and retracted relativeto the base unit by movement of the leg relative to the housing. In thiscase, the apparatus preferably comprises four legs that are arrangedparallel to one another.

Two or more of the anchorages, and hence their associated legs, may bemechanically connected so as to facilitate coordinated movement of theanchorages. Alternatively, coordinated movement of the legs andanchorages may be achieved by means of a microprocessor and suitablesensors. In particular, since structures under construction generallyinclude pairs of parallel beams, the apparatus is preferably arrangedsuch that the anchorages are always arranged along two parallel lines.

The operation of the anchorages is preferably controllable by aconstruction worker accommodated by the base unit. In addition, themovement of the anchorages relative to the base unit is preferablycontrollable by a construction worker accommodated by the base unit. Inparticular, the base unit preferably includes a control panel thatenables a construction worker to control said operation and/or movementof the anchorages, and hence also any legs supporting the anchorages.The control panel preferably includes, or is in communication with, asuitable control device, such as a microprocessor. Most preferably, thecontrol panel is connected to the microprocessor and/or the anchoragessuch that the control panel is movable by the construction workerrelative to the base unit. In particular, the control panel ispreferably connected to the microprocessor and/or the anchorages bymeans of a flexible cable or a wireless link.

Preferably, each anchorage and leg is operated and/or moved using ahydraulic or electromechanical transmission system. The control panel ispreferably only functional when the boom and work platform are in aconfiguration that is suitable for transportation of the apparatus. Inaddition, the control panel preferably includes a selector switch thatmust be in an appropriate state for the control panel to function.

Each anchorage preferably has the general form of a clamp that isarranged to captivate a beam or the like of a structure. Mostpreferably, each anchorage comprises first and second clamp members thatare movable relative to one another so as to captivate a beam or part ofa beam between the clamp members on actuation of the anchorage. Inaddition, each anchorage preferably includes a location surface that isadapted to lie against a surface of the beam, such that the beam or partof a beam is captivated between the location surface and the clampmembers on actuation of the anchorage.

In presently preferred embodiments, each anchorage is adapted forengagement with a flange of a beam comprising a pair of flanges joinedby a connecting web. However, each anchorage may also be able to engagebeams having a range of different cross-sectional shapes, such ascircular, rectangular or hexagonal cross-sections. In this case, thelocation surface is preferably adapted to lie against an outer face ofthe flange, and the clamp arms are preferably adapted to engage an innerface of the flange on each side of the connecting web, such that theflange is captivated, in use, between the location surface and the firstand second clamp members.

The clamp preferably comprises a housing to which the first and secondclamp members are preferably mounted. The location surface is preferablydefined by the housing, but may be defined by a separate locationmember. In addition, the housing may define one of the first and secondclamp members.

Most preferably, the clamp includes a depression within which the flangeis received, in use, as the location surface is brought alongside theouter face of the flange. This depression may be defined by the housingalone, or together with one or both of the clamp members. Mostpreferably, the depression is defined substantially by the housing, andis tapered so as to aid location of the flange alongside the locationsurface.

One or both of the first and second clamp members may be rotatablymounted relative to the location surface, such that the clamp membersmay be brought into engagement with the inner face of the flange oncethe location surface has been located alongside the outer face of theflange.

In presently preferred embodiments, however, the first clamp member ismounted for linear movement relative to the second clamp member, andalso preferably relative to the housing and the location surface. Mostpreferably, the first clamp member is mounted for linear movement in theplane of the location surface. This linear movement is preferablyactuated by a hydraulic ram or the like. This arrangement enables beamshaving a larger range of cross-sectional shapes and sizes to be engagedby the clamp.

In this case, the first clamp member and/or the second clamp memberpreferably has an operable face that is inclined relative to theoperable face of the location surface, and hence the inner face of theflange, such that the operable face is able to engage a peripheral partof the inner face of the flange. Alternatively, the first clamp memberand/or the second clamp member may be rotatable relative to the locationsurface so that the clamp member may be rotated into engagement with theinner face of the flange. This rotation may be effected by a suitabledrive mechanism that is controlled by a user, but most preferably thisrotation is effected by the flange impinging upon the clamp memberduring use. In presently preferred embodiments, the first clamp memberhas an inclined operable face, and the second clamp member is rotatablerelative to the location surface, as described above.

Each anchorage may be rotatable relative to the leg on which it ismounted. In particular, the orientation of each anchorage relative toits corresponding leg may be determined by an appropriate drivemechanism and controllable from the control panel of the base unit.Alternatively, each anchorage may be resiliently biased into a restorientation, and rotated in use by engagement with the beam to which theanchorage is to be fixed.

However, in presently preferred embodiments, each anchorage is fixed toone end of a leg. In this case, the first clamp member is preferablymounted to a carriage, which is itself mounted within the leg andincludes a mechanism for moving the carriage relative to the leg, suchthat the first clamp member may be moved along a linear path relative tothe leg. In particular, the carriage is preferably slidably mountedwithin the leg.

Most preferably, the second clamp member has a fixed linear positionrelative to the leg. Hence, the first and second clamp members arepreferably brought into engagement with the flange by extension of theleg until the second clamp member engages the flange, and retraction ofthe carriage until the first clamp member engages the flange. Thesemovements may be effected together, or in sequence, as appropriate.

The apparatus is preferably provided with a transportation frame uponwhich the apparatus is able to be mounted so that the apparatus may bereadily transported on a truck or the like. In particular, thetransportation frame preferably comprises a pair of cross-members thatare arranged so that apparatus according to the invention may bereleasably fixed to the cross-members. For example, the cross-membersmay have the form of I-section beams.

Preferred embodiments of the invention will now be described in greaterdetail, by way of illustration only, with reference to the accompanyingdrawings, in which

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a first embodiment of apparatusaccording to the invention secured to a pair of parallel beams;

FIG. 2 is a perspective view of the arrangement of FIG. 1 with theapparatus in an extended configuration;

FIG. 3 is a perspective view of a base unit that forms part of the firstembodiment of apparatus according to the invention;

FIG. 4 is an end view of a first beam, and a clamp unit forming part ofthe first embodiment of apparatus according to the invention;

FIG. 5 is an end view of a second beam, and the clamp unit forming partof the first embodiment of apparatus according to the invention;

FIG. 6 is an end view of a first beam, and a first alternative clampunit for use with the first embodiment of apparatus according to theinvention;

FIG. 7 is a perspective view of a first beam, and a second alternativeclamp unit for use with the first embodiment of apparatus according tothe invention;

FIG. 8 is a perspective view of a first beam, and a third alternativeclamp unit for use with the first embodiment of apparatus according tothe invention;

FIG. 9 is a perspective view of an alternative, and presently preferred,base unit for use with the first embodiment of apparatus shown in FIGS.1 and 2;

FIG. 10 is a fragmentary perspective view of the base unit of FIG. 9;

FIG. 11 is a fragmentary side view of the base unit of FIG. 9 and 10;

FIG. 12 is a side view of a clamp of the base unit of FIGS. 9 to 11 inwhich the clamp is in an open configuration;

FIG. 13 is a view similar to that of FIG. 12 showing the clamp in afirst stage of engagement with a beam;

FIG. 14 is a view similar to that of FIG. 13 showing the clamp in asecond stage of engagement with a beam;

FIG. 15 is a view similar to that of FIG. 14 showing the clamp engagedwith a beam;

FIG. 16 is a perspective view of a second embodiment of apparatusaccording to the invention incorporating the base unit of FIG. 9, inwhich the apparatus is in an extended configuration;

FIG. 17 is a perspective view of the second embodiment in a retractedconfiguration;

FIG. 18 is a plan view of a transportation frame for use with apparatusaccording to the invention; and

FIG. 19 is a side view of the transportation frame.

DETAILED DESCRIPTION

FIGS. 1 and 2 show a first embodiment of apparatus according to theinvention, which is generally designated 10, fixed to a pair of parallelhorizontal beams 12. The apparatus 10 comprises a base unit 20 having acentral support plinth 22, four legs 30 extending from the base unit 10with each leg 30 including a clamp unit 32 at its outer end, a support40 rotatably mounted to the support plinth 22, a boom 50 extending fromthe support 40, and a work platform 60 for accommodating a constructionworker at the outer end of the boom 50. The apparatus 10 according tothe invention is formed in a suitably strong, durable andweather-resistant metal, such as steel.

Referring now also to FIG. 3, the base unit 20 comprises a framework ofsteel members. The framework of the base unit 20 includes an upperrectangular part 24 and a lower rectangular part 26 that are connectedto each other by eight pillars 25. The pillars 25 are regularly spacedapart around the periphery of the base unit 20. The base unit 20 furtherincludes a central support plinth 22, and a pair of diagonalcross-members (not shown in FIG. 3) extending across each of the upperand lower rectangular parts 24,26 of the base unit 20.

Each leg 30 of the apparatus 10 is pivotally mounted, at a point that isnear to its inner end, between the upper and lower rectangular parts 24,26 at a corner of the base unit 20. Each leg 30 is orientated in theplane in which the base unit 20 is orientated, and is capable ofrestricted rotation relative to the base unit 20 about an axis that isorientated perpendicularly to that plane. A pair of hydraulic rams 23extend away from the central support plinth 22 towards opposite sides ofthe base unit 20. The outer end of each hydraulic ram 23 is pivotallyattached to a pair of identical connecting arms 28. Each of theseconnecting arms 28 is pivotally attached to the inner end of an adjacentleg 30, as shown most clearly in FIG. 3.

When one of the hydraulic rams 23 is in its fully retracted state, thepair of connecting arms 28 attached to that hydraulic ram 23 act toorientate the two legs 30 to which the connecting arms 30 are attachedso that they are parallel to each other. When one of the hydraulic rams23 is in its fully extended state, the pair of connecting arms 28attached to that hydraulic ram 23 act to orientate the two legs 30 towhich the connecting arms 30 are attached so that they are at an angleof approximately 90° to each other. In this way, each pair of connectedlegs 30 can be orientated relative to the base unit 30 according to thearrangement of the beams 12 or the like to which the base unit 20 is tobe fixed.

Each leg 30 comprises an outer component which is pivotally mounted tothe base unit 20, and an inner component which is slidably mountedwithin the outer component. The inner and outer components of each leg30 are tubular in form, with a rectangular cross-section. A hydraulicram (not visible in FIG. 3) acts between the outer component and theinner component so that each leg 30 is telescopically extendible andretractable. A clamp unit 32 (not shown in FIG. 3) is bolted to thelower surface of the inner component of the leg 30, at the outer end ofthe leg 30. In this way, each leg 30 can be extended or retracted, andhence each clamp unit 32 positioned relative to the base unit 30,according to the arrangement of the beams 12 or the like to which thebase unit 20 is to be fixed.

The base unit 20 has a floor (which is transparent in FIGS. 1 and 2, andomitted from FIG. 3, for clarity) that is supported at its periphery bythe upper rectangular part 24 of the base unit 20, and along a pair ofdiagonal lines by the diagonal cross-members of the base unit 20. Thefloor of the base unit 20 is formed of expanded metal, and the centralsupport plinth 22 extends a little distance above the floor.

The support 40 comprises a base plate that is rotatably mounted to thesupport plinth 22, and a rotation mechanism (not shown in the Figures)that causes the support 40 to rotate relative to the support plinth 22and hence the base unit 20. The support 40 further comprises a generallyupright support member that is hingedly mounted to the upper surface ofthe base plate, and a hydraulic ram that is hingedly mounted at one endto the upper surface of the base plate and at the other end to an upperpart of the support member. The hydraulic ram of the support 40 acts toalter the inclination of the support member relative to the base unit 20as desired.

A pair of parallel arms extend generally perpendicularly away from theupper end of the support member, and a proximal end of the boom 50 ishingedly mounted between these arms. A hydraulic ram 52, which ispivotally mounted at one end to an upper part of the support 40 and atthe other end to a connecting arm that is itself pivotally connected toa part of the boom 50 adjacent to its proximal end, acts to rotate theboom 50 relative to the support 40 about a single horizontal axis. Thelimits of this rotation will depend upon the geometry of the support 40,the boom 50 and the hydraulic ram 52. In the embodiment shown in FIGS. 1and 2, the boom 50 is rotatable up to approximately 70° above thehorizontal plane and approximately 15° below the horizontal plane.However, it will be clear to the skilled person that greater degrees ofrotation may be achieved by altering the geometry of the support 40, theboom 50 and the hydraulic ram 52. The boom 50 comprises three tubularcomponents that are slidably engaged with one another, and the boom 50is telescopically extendible and retractable.

A work platform 60 is connected to the distal end of the boom 50 by apair of parallel connecting members 61 of equal length. The connectingmembers 61 are each pivotally attached at one end to a vertical wall ofthe work platform 60, and at the other end to a vertically-orientatedlink 63 at the distal end of the boom 50. The vertical wall of the workplatform 60, the connecting members 61, and the link 63, are arranged soas to define a parallelogram, and the apparatus 10 further includes ahydraulic ram 62 that acts along a diagonal of that parallelogram so asto alter the shape thereof. Actuation of the hydraulic ram 62 thereforeacts to raise or lower the work platform 60 relative to the link 63 andthe boom 50.

The work platform 60 is maintained in a horizontal orientation,regardless of the orientation of the boom 50, by a self-levellingsystem. The self-levelling system comprises a microprocessor forcontrolling a hydraulic ram (not visible in the Figures) mounted insidethe boom 50. The hydraulic ram within the boom 50 acts to alter theorientation of the link 63 relative to the boom 50. The self-levellingsystem either continuously or intermittently senses the orientation ofthe work platform 60 and/or link 63, during use, and when necessaryactivates the hydraulic ram within the boom so as to maintain the link63 with a vertical orientation, and hence maintain the base of the workplatform 60 with a horizontal orientation, at all times regardless ofthe orientation of the boom 50.

The apparatus 10 also includes a mechanism for rotating the link 63about its longitudinal axis so that the connecting members 61 arerotated relative to the boom 50 about a vertical axis through an angleof up to 180°. The apparatus 10 further includes a mechanism forrotating the work platform 60 relative to the connecting members 61about a vertical axis through an angle of up to 180°. These mechanismsenable the work platform 60 to move within a generally horizontal planerelative to the boom 50. In this way, the work platform 60 can bemanoeuvred, in use, around obstacles such as vertical beams.

Rotation and inclination of the support member relative to the baseunit, rotation of the boom 50 relative to the support member, andtelescopic extension and retraction of the boom 50, are each controlledby the construction worker using a control panel (not shown in theFigures) mounted on the work platform 60.

FIGS. 4 and 5 show the clamp unit 32 of the apparatus 10 described abovepositioned above a beam 11,12 before the clamp unit 32 has been actuatedinto engagement with the beam 11,12. The beam 12 shown in FIG. 4, aswell as in FIGS. 1, 2, 6, 7 and 8, is an I-section steel beam with adepth of 300 mm. The beam 11 shown in FIG. 5 is an I-section beam with adepth of 140 mm. Each beam 11,12 comprises horizontally-orientated upperand lower flanges that are separated by a vertically-orientatedconnecting web.

The clamp unit 32 comprises a housing 33 that is bolted at its upper endto its associated leg 30 (not shown in FIGS. 4 and 5), a pair ofhydraulic rams 34, a locating member 35, and a pair of clamp arms 38.The locating member 35 is a generally cylindrical body that extendsdownwardly from the lower surface of the housing 33 and has a flat lowersurface.

The housing 33 includes two pairs of flanges 36 that extend downwardlyfrom its lower surface. Each clamp arm 38 is pivotally mounted between apair of flanges 36, at a point between its ends, so that the clamp arms38 are able to rotate relative to the housing 33. Each hydraulic ram 34is pivotally attached at one end to a wall of the housing 33, and at theother end to the upper end of the clamp arm 38 that is situated adjacentto the opposing wall of the housing 33. Extension and retraction of thehydraulic rams 34 causes the clamp arms 38 to rotate relative to thehousing 33.

Before engagement, the hydraulic rams 34 are retracted until the clamparms 38 are positioned such that the clamp unit 32 can be lowered untilthe locating member 35 contacts the upper surface of the beam 11,12. Onactuation of the clamp unit 32, the hydraulic rams 34 are extended,thereby rotating the clamp arms 38, until the ends of the clamp arms 38that are remote from the hydraulic rams 34 are brought into abutmentwith the lower surface of the upper flange of the beam 11,12. In thisway, the clamp unit 32 captivates the flange of the beam 11,12 betweenthe locating member 35 and the clamp arms 38, and hence fixes theapparatus 10 to the beam 11,12. The clamp arms 38 engage a central partof the upper flange of the beam 11,12, thereby enabling the clamp unit32 to captivate a range of differently sized beams 11,12.

FIG. 6 shows a first alternative clamp unit 132 for use with theapparatus described above. The clamp unit 132 is shown in apre-engagement position relative to a beam 12. The clamp unit 132comprises a housing 133 that is bolted at its upper end to itsassociated leg 30 (not shown in FIG. 6), a locating member 135, acarriage 136 that is acted on by a first hydraulic ram 134, and a clamparm 138 that is acted on by a second hydraulic ram 137.

The housing 133 includes a vertical locating surface that is broughtinto abutment with one end of the upper flange of the beam 12, in use,and a locating member 135 that extends from the upper end of thatsurface and includes a horizontal lower surface that is brought intoabutment with the upper surface of the beam 12, in use. The housing 133further includes an upper member that extends above, and parallel with,the upper surface of the beam 12. The carriage 136 is slidably mountedto the upper member of the housing 133, and is acted upon by the firsthydraulic ram 134 which is mounted within the housing 133.

The carriage 136 includes adjacent vertical and horizontal surfaces atits lower end that are brought into abutment with the other side of theupper flange of the beam 12, and the upper surface of the beam 12,respectively, as the first hydraulic ram 134 is retracted and hence thecarriage 136 is moved towards the beam 12, in use. The clamp arm 138 ispivotally attached to the carriage 136 at a point near to the upper endof the arm 138, and the upper end of the arm 138 is pivotally attachedto the second hydraulic ram 137 which is mounted within the carriage136.

Before engagement, the first hydraulic ram 134 is extended, and thesecond hydraulic ram 137 is retracted, such that the clamp unit 132 canbe positioned with the locating member 135 and the horizontal surface ofthe carriage 136 contacting the upper surface of the beam 12, and thevertical surface of the housing 133 contacting one end of the upperflange of the beam 12. On actuation, the first hydraulic ram 134 isretracted until the vertical surface of the carriage 136 is brought intoabutment with the other end of the upper flange of the beam 12 to thatengaged by the housing 133, and the second hydraulic ram 137 is thenextended until the clamp arm 138 is brought into abutment with the lowersurface of the upper flange of the beam 12. In this way, the clamp unit132 captivates the upper flange of the beam 12 between the locatingmember 135, the carriage 136, and the clamp arm 138, and hence fixes theapparatus 10 to the beam 12.

FIG. 7 shows a second alternative clamp unit 232 for use with theapparatus 10 described above. The clamp unit 232 is shown in engagementwith a beam 12. The clamp unit 232 comprises a housing 233 that isbolted at its upper end to its associated leg 30 (not shown in FIG. 7),a locating member 235 extending downwardly from the lower end of thehousing 233, and a pair of clamp arms 238 that are acted on by a pair ofhydraulic rams (not visible in FIG. 7) within the housing 233.

Each clamp arm 238 is pivotally mounted at a point near to its upper endwithin the housing 233. Hydraulic rams act on the clamp arms 238 so asto cause rotation of the clamp arms 238 into, and out of, engagementwith the beam 12. Each clamp arm 238 has a generally channel-shapedcross-section for increased strength.

Before engagement, the clamp arms 238 are positioned so that the clampunit 232 can be lowered until the locating member 235 contacts the uppersurface of the beam 12. On actuation, the clamp arms 238 are rotatedrelative to the housing 233 until they are brought into abutment withthe lower surface of the upper flange of the beam 12. In this way, theclamp unit 12 captivates the upper flange of the beam 12 between thelocating member 235 and the clamp arms 238, and hence fixes theapparatus 10 to the beam 12.

Finally, FIG. 8 shows a third alternative clamp unit 332 for use withthe apparatus 10 described above. The clamp unit 332 is shown in apre-engagement position relative to a beam 12. The clamp unit 332comprises a housing 333 that is bolted at its upper end to itsassociated leg 30 (not shown in FIGS. 4 and 5), a locating member 335,and a clamp arm 338 that is acted upon by a hydraulic ram 334.

The clamp arm 338 is slidably mounted within the housing 333, andprojects downwardly therefrom. The portion of the clamp arm 338 thatprojects from the housing 333 is formed with an inwardly facing recessthat is adapted to receive one end of the upper flange of the beam 12.The hydraulic ram 334 is mounted within the housing 333, and acts toslide the clamp arm 338 relative to the housing 333. The locating member335 has an upper portion that is slidably mounted within a lower part ofthe housing 333 and has a lower surface adapted to be brought intoabutment with the upper surface of the beam 12, and a projection thatextends downwardly from the end of the upper portion that is remote fromthe clamp arm 338. The projection of the locating member 335 has avertical surface that is adapted to be brought into abutment with theother end of the upper flange of the beam 12 to that which is to bereceived by the clamp arm 338.

Before engagement, the locating member 335 is positioned relative to thehousing 333 such that the beam 12 will be centrally positioned relativeto the clamp unit 332 when the horizontal and vertical surfaces of thelocating member 335 are brought into contact with the upper surface ofthe beam 12, and one end of the upper flange of the beam 12,respectively. The locating member 335 is secured in this position by apair of latching pins 336 that are fastened within opposing openings inthe housing 333. Once the locating member 335 has been secured in thisposition, the horizontal and vertical surfaces of the locating member335 are brought into contact with the upper surface of the beam 12, andone end of the upper flange of the beam 12, respectively. The clamp unit332 is then actuated causing the first hydraulic ram 334 to be retracteduntil the recess of the clamp arm 338 receives the other end of theupper flange of the beam 12 to that engaged by the locating member 335.In this way, the clamp unit 332 captivates the upper flange of the beam12 between the locating member 335 and the clamp arm 338, and hencefixes the apparatus 10 to the beam 12. The third alternative clamp unit332 is therefore able to engage beams of different widths.

As discussed above, buildings are typically constructed by first forminga building framework on suitable foundations, and then forming thefloors and walls of the building about the building framework. Thebuilding framework generally comprises a plurality of verticallyorientated steel columns to which horizontally orientated steel beamsare attached to form a floor-supporting framework for each floor of thebuilding. The horizontally orientated steel beams of each completedfloor-supporting framework typically have the form of a square orrectangular grid.

Before use, the legs 30 of the apparatus 10 are rotated, and eitherextended or retracted, until the clamp units 32, 132, 232, 332 areappropriately positioned to engage with two parallel horizontal beams ofa complete floor-supporting framework.

Whilst the apparatus 10 according to the invention is resting upon theground, or on a transporting heavy goods vehicle, one or moreconstruction workers enter the base unit 20 and secure themselves to thesafety rail of the base unit 20 using safety harnesses.

The apparatus 10 is then lifted using a tower crane or the like andsuspended above two parallel horizontal beams of a completefloor-supporting framework. The legs 30 of the apparatus 10 are rotated,and either extended or retracted, until the clamp units 32,132,232,332are appropriately positioned to engage with the two parallel horizontalbeams. The apparatus 10 is then lowered until the upper surface of eachbeam supports a pair of clamp units 32,132,232,332, and the clamp units32,132,232,332 are actuated so as to secure the apparatus 10 to thefloor-supporting framework.

Alternatively, the clamp unit 332 shown in FIG. 8 may be rotatablymounted to its corresponding leg, and biased by an appropriate springmechanism (not shown in FIG. 8) into a rest position in which thehousing 333 is orientated generally parallel to the leg. In this case,the apparatus 10 is lifted using a tower crane or the like and suspendedbetween two parallel horizontal beams of a complete floor-supportingframework. In this position, the lower end of the clamp arm 338 of eachclamp unit 332 is in a raised location relative to the upper surface ofthe corresponding beam, and the lower end of the locating member 335 ofeach clamp unit 332 is in a lowered location relative to the uppersurface of the corresponding beam.

The legs 30 of the apparatus 10 are extended and then rotated until thelocating members 335 of the clamp units 332 contact the beams. Furtherrotation of the legs 30 will cause each clamp unit 332 to rotaterelative to its associated beam until the clamp arm 338 is situated onthe opposite side of the beam to the locating member 335. The apparatus10 is then lowered until the clamp units 332 are supported by the uppersurface of the beams, and the clamp units 332 are actuated so as tosecure the apparatus 10 to the floor-supporting framework.

In either case, the one or more construction workers may then enter thework platform 60, and transport themselves to a fixing site using thecontrol panel mounted on the work platform 60. A tower crane or the liketransports construction material to the fixing site so that theconstruction workers, whilst safely accommodated within the workplatform 60, can fix the construction material to the structure. As theapparatus 10 is fixed to the structure before being used to transportconstruction workers to the fixing site, the risk of accidents occurringwhile the apparatus 10 is supported by the partially constructedstructure is reduced.

FIG. 9 shows an alternative, and presently preferred, base unit 420 foruse with the apparatus of FIGS. 1 and 2. In particular, the base unit420 is shown engaged with a pair of parallel beams 12.

The base unit 420 comprises a central housing 422 upon which the support40, boom 50 and work platform 60 of the apparatus shown in FIGS. 1 and 2are mounted. However, the support 40 for use with this base unit 440includes a platform with safety rail (not shown in the Figures) foraccommodating a construction worker. The support 40 and associatedplatform are rotatably mounted to the central housing 422, and asuitable drive mechanism (not shown in the Figures) is provided forrotating the support 40 and platform relative to the base unit 420during use. In this embodiment, the drive mechanism comprises a ringgear that is mounted to the base unit 420 and cooperates via a bearingsystem with a worm or gearbox drive that is mounted to the support 40and associated platform. In addition, connection apparatus 424 forguiding oil and electrical circuits between the support 40 and thecentral housing 422 is also provided.

The central housing 422 includes a pair of parallel side walls to eachof which is fixed an inner leg housing 426. The inner leg housings 426are each generally box-section members that extend parallel to the sidewalls of the housing 422 to which they are fixed, and extend a littlebeyond the length of the side walls at each end. Furthermore, identicalouter leg housings 428 are mounted adjacent and parallel to the innerleg housings 426.

A leg 440 is mounted within each of the inner and outer leg housings426,428, such that the base unit 420 comprises four legs 440, two oneach side of the central housing 422. Each leg 440 is defined by twochannel-section members that are fixed to one another such that the leg440 is of box-section construction. Each leg 440 is slidably mountedwithin its associated leg housing 426,428 so as to be movable relativeto the leg housing 426,428 along its longitudinal axis. The four legs440 are therefore at all times parallel to one another during use.

A clamp 430, which is described in more detail below with reference toFIGS. 10 to 15, is formed at an end of each of the four legs 440, suchthat the base unit 420 has front and rear ends that each have a pair ofclamps 430 (the clamps 430 at the far end of the base unit 420 arehidden) with a pre-determined and constant separation.

Each leg 440 is also provided with an external hydraulic ram 442 thatactuates movement of the leg 440 relative to the associated leg housing446,448. In particular, each external hydraulic ram 442 extends alongthe upper surface of that leg housing 446,448, and is fixed at one endto an end of a leg housing 446,448, and at its other end to the clamp430 at the end of the associated leg 440.

A hose- and cable-carrying tray 444 is provided for each leg 440, at theopposite end of the leg 440 from the clamp 430. Each tray 444 extendsbetween the leg 440 and a platform 445 that is fixed to an end of theleg housings 446,448. Hydraulic hoses and cables for the mechanisms andassociated sensors of a particular leg 440 extend along the platform 445and through the tray 444 to that leg 440.

Turning now also to FIGS. 10 and 11, the clamp 430 comprises a pair ofmounting plates 432, an inner clamp member 436 and an outer clamp member435. The mounting plates 432 are fixed to either side of an end portionof the leg 440, and each comprise a pair of lower projections thattogether define a generally trapezoidal depression for receiving atleast a flange of the beam 12 during use. The surfaces of the mountingplates 432 that define this depression include a surface that isorientated parallel to the associated leg 440. This surface defines alocation surface of the clamp 430 that is adapted to lie alongside theupper surface (as viewed in FIG. 11) of the beam 12 during use.

The mounting plates 432 also include an upper projection to which ismounted an end of the external hydraulic ram 442. In this way, actuationof the external hydraulic ram 442 effects movement of the leg 440 andmounting plates 432 relative to housings 422,426,428 of the base unit420.

The inner clamp member 436 comprises four mounting arms, two of whichare rotatably mounted either side of one mounting plate 432 and two ofwhich are rotatably mounted either side of the adjacent mounting plate432. The mounting arms are identical to one another in shape, and arearranged in registration with one another. Furthermore, each mountingarm is generally arcuate in form so as to define a concave surface thatfaces the outer clamp member 435 and is situated adjacent to thelocation surface of the clamp 430. The portion of the concave surfacethat is immediately adjacent to the location surface of the clamp 430 isadapted for engagement by the flange of the beam 12, as discussed inmore detail below with reference to FIGS. 12 to 15. The inner clampmember 436 further includes an engagement bar that is mounted to theother end of the concave surface, the engagement bar being adapted toengage the underside of the flange of the beam 12.

The outer clamp member 435 is mounted for linear movement relative tothe mounting plates 432 and the inner clamp member 436 in a directionthat is parallel to the associated leg 440. In particular, the outerclamp member 435 is mounted to an end of a carriage 434 that is slidablymounted within the leg 440. The carriage 434 has the form of abox-section member, and is aligned along a generally centrallongitudinal axis of the leg 440. An inner hydraulic ram is mountedwithin the interior of the leg 440, and acts to effect movement of thecarriage 434, and hence the outer clamp member 435, relative to theremainder of the clamp 430.

The outer clamp member 435 comprises an engagement surface that isinclined relative to the location surface of the clamp 430 so as todefine an recess therebetween. Furthermore, this recess faces the innerclamp member 436. As shown most clearly in FIG. 10, the upperchannel-section member of each leg 440 extends a greater distance thanthe lower channel-section member, such that the outer clamp member 435projects from the underside of the leg 440 into the depression definedby the mounting plates 432, and the outer clamp member 435 is able tomove along almost the entire extent of the location surface of the clamp430.

FIG. 12 to 15 illustrate engagement of the clamp 430 with an I-sectionbeam 12. In FIG. 12, the carriage 434 is fully extended from the leg 440so that the outer clamp member 435 does not extend into the depressiondefined by the mounting plates 432. In use, the clamp 430 is lowereduntil the location surface rests upon the upper surface of the beam 12,as shown in FIG. 12. The carriage 434 is then retracted until theengagement surface of the outer clamp member 435 engages a peripheralpart of the underside of the flange of the beam 12, as shown in FIG. 13.The leg 440 is then extended, whilst at the same time retracting thecarriage 434 so that the outer clamp member 435 remains engaged with thebeam 12, until the flange of the beam 12 engages the portion of theconcave surface of the inner clamp member 436 that is immediatelyadjacent to the location surface, as shown in FIG. 14, and causes theinner clamp member 436 to rotate until the engagement bar of the innerclamp member 436 engages the underside of the flange, as shown in FIG.15.

In use, apparatus including the base unit 420 of FIG. 9 is lifted usinga tower crane or the like and suspended above two parallel horizontalbeams 12 of a complete floor-supporting framework. The apparatus issuspended from the support 40 and associated platform, such that thebase unit 420 of the apparatus may be rotated relative to the beams 12.The base unit 420 is rotated until the legs 440 are orientatedperpendicularly to the two parallel beams 12. The legs 440 are thenextended or retracted until the clamps 430 are appropriately positionedto engage with the two parallel horizontal beams 12. The apparatus isthen lowered until the location surface of the each clamp 430 liesalongside the upper surface of each beam 12. The clamps 430 are thenactuated, as described above, so as to secure the apparatus to thefloor-supporting framework.

One or more construction workers may then enter the work platform 60,and transport themselves to a fixing site using the control panelmounted on the work platform 60. A tower crane or the like transportsconstruction material to the fixing site so that the constructionworkers, whilst safely accommodated within the work platform 60, can fixthe construction material to the structure. Since the apparatus is fixedto the structure before being used to transport construction workers tothe fixing site, the risk of accidents occurring while the apparatus issupported by the partially constructed structure is reduced.

FIGS. 16 and 17 show a second embodiment of apparatus according to theinvention, which is generally designated 510. The second embodiment 510incorporates the base unit 420 shown in FIG. 9. In FIGS. 16 and 17, theplatform 520 and safety rail 524 of the base unit 420, which accommodateone or more construction workers during use, are clearly shown.

The boom 550 and work platform 560 of the apparatus 510 are essentiallythe same as the boom 50 and work platform 60 of the first embodiment 10.However, the support 540 of the second embodiment 510 differs in that itis extendible along a generally vertical axis during use by means of anadditional linkage 542 and an additional hydraulic ram (not visible inthe Figures). This support 540 enables the apparatus 510 to elevate thework platform 540 to greater heights, without increasing the length ofthe boom 550.

When the support 540 and boom 550 are fully retracted, as shown in FIG.17, the work platform 560 is positioned adjacent to one end of theplatform 522 of the base unit 420. In particular, a gate 526 is providedin the safety rail 524 of the base unit 420, and a gate 562 is providedin the safety rail of the work platform 560, so that a constructionworker is able to safely move from the base unit 420 to the workplatform 560 during use.

Finally, FIGS. 18 and 19 show a transportation frame for the apparatus10,510 according to the invention, which is generally designated 600.The transportation frame 600 comprises a rectangular frame 602 ofbox-section members, and two I-section cross-members 604 that are weldedto the upper surface of the rectangular frame 602. In particular, thetwo cross-members 604 extend across the width of the rectangular frame602, and an upright location member 606 is formed at each end of thecross-members 604. The transportation frame 600 also includes four lugs608, each including an aperture, to enable attachment of thetransportation frame 600 to a crane.

The cross-members 604 are arranged so that apparatus 10,510 according tothe invention may be mounted upon the cross-members 604. In thisconfiguration, the transportation frame 600 and the apparatus 10,510according to the invention may be raised by a crane or the like onto atruck, for example, for transportation. The cross-members 604 are alsoarranged so that the centre of gravity of the transportation frame 600and the apparatus 10,510 according to the invention is located generallycentrally relative to the crane attachment lugs 608.

Finally, two parallel receiving members 610 of box-section extend acrossthe width of the rectangular frame 602 between openings 611 formed inthe side walls of the rectangular frame 602. The receiving members 610and openings 611 are adapted to receive the forks of a forklift truck orthe like so that the transportation frame 600, including the apparatus10,510 according to the invention, may be lifted onto a transportationtruck, for example. A strengthening member 612 is fixed to thecross-members 604 and the receiving members 612, and extends along thelongitudinal axis of the transportation frame 600, so as to give thetransportation frame 600 greater strength and stability during use.

1. Apparatus for use in construction, which apparatus comprises a baseunit adapted to be releasably fixed to a structure in an elevatedposition relative to the ground, and a mechanism for moving aconstruction worker and/or construction material relative to thestructure.
 2. Apparatus as claimed in claim 1, wherein the base unit isadapted to accommodate a construction worker.
 3. Apparatus as claimed inclaim 2, wherein the base unit is adapted to accommodate a constructionworker whilst the apparatus is raised relative to the structure. 4.Apparatus as claimed in claim 3, wherein the base unit satisfiesrecognized safety standards relating to transportation platforms forconstruction workers.
 5. Apparatus as claimed in any one of claim 2,wherein the base unit comprises a floor and a peripheral barrier. 6.Apparatus as claimed in claim 1, wherein the apparatus is adapted to becoupled to a crane.
 7. Apparatus as claimed in claim 1, wherein theapparatus includes a mechanism for raising itself relative to thestructure.
 8. Apparatus as claimed in claim 7, wherein the apparatusincludes a raising mechanism that cooperates with horizontal and/orvertical beams of the structure to raise the apparatus relative to thestructure.
 9. Apparatus as claimed in claim 8, wherein operation of theraising mechanism is controllable by a construction worker accommodatedby the base unit.
 10. Apparatus as claimed in claim 8, wherein theraising mechanism is adapted for fixing the base unit to the structurein an elevated position relative to the ground.
 11. Apparatus as claimedclaim 1, wherein the apparatus comprises a mechanism for movingconstruction material relative to the base unit.
 12. Apparatus asclaimed in claim 11, wherein the mechanism for moving constructionmaterial comprises a winch.
 13. Apparatus as claimed in claim 1, whereinthe apparatus comprises a mechanism for moving a construction workerrelative to the base unit.
 14. Apparatus as claimed in claim 13, whereinthe mechanism for moving a construction worker relative to the base unitincludes a work platform that is adapted for accommodating aconstruction worker, and a mechanism for moving the work platformrelative to the base unit.
 15. Apparatus as claimed in claim 14, whereinthe apparatus comprises a support body mounted on the base unit, and aboom extending between the support body and the work platform. 16.Apparatus as claimed in claim 15, wherein the support body is rotatablymounted on the base unit.
 17. Apparatus as claimed in claim 15, whereinthe boom is pivotally mounted at one end to the support body, and at theother end to the work platform.
 18. Apparatus as claimed in claim 17,wherein the apparatus includes a mechanism for rotating the boomrelative to the support body about a single horizontal axis. 19.Apparatus as claimed in claim 17, wherein the apparatus includes amechanism for rotating the work platform relative to the boom about asingle horizontal axis.
 20. Apparatus as claimed in claim 19, whereinthe apparatus includes a self-leveling system that maintains the workplatform in a generally horizontal orientation.
 21. Apparatus as claimedin claim 20, wherein the self-leveling system is controlled by amicroprocessor, such that the system either continuously orintermittently senses the orientation of the work platform, andautomatically maintains the work platform in a horizontal orientationduring use.
 22. Apparatus as claimed in claim 1, wherein the boom istelescopically extendible and retractable.
 23. Apparatus as claimed inclaim 22, wherein the boom comprises a plurality of tubular members thatare slidably engaged with one another.
 24. Apparatus as claimed in claim15 wherein the apparatus includes a mechanism for rotating the workplatform relative to the boom about at least one generally verticalaxis.
 25. Apparatus as claimed in claim 15, wherein the apparatusincludes at least one connecting member that couples the boom and thework platform together.
 26. Apparatus as claimed in claim 25, whereinthe connecting member is pivotally connected to the boom at one end, andpivotally connected to the work platform at the other end.
 27. Apparatusas claimed in claim 26, wherein the apparatus includes a mechanism forrotating the connecting member relative to the boom about a firstvertical axis, and a mechanism for rotating the work platform relativeto the connecting member about a second vertical axis, such that thework platform is moved within a generally horizontal plane relative tothe boom.
 28. Apparatus as claimed in claim 1, wherein the base unitcomprises a floor and a peripheral barrier in the form of a safety rail.29. Apparatus as claimed in claim 14, wherein the position of the workplatform relative to the base unit is controllable by the constructionworker accommodated by the work platform.
 30. Apparatus as claimed inclaim 29, wherein a control panel is mounted to the work platform toenable the construction worker to move the work platform relative to thebase unit.
 31. Apparatus as claimed in claim 30, wherein the controlpanel on the base unit includes a selector switch that must be in anappropriate state for the control panel on the work platform tofunction.
 32. Apparatus as claimed in claim 1, wherein the apparatuscomprises a plurality of anchorages for fixing the base unit to astructure such that the base unit is in an elevated position relative tothe ground.
 33. Apparatus as claimed in claim 32, wherein one or more ofthe anchorages are movably mounted relative to the base unit. 34.Apparatus as claimed in claim 32, wherein the anchorages are adapted toengage one or more beams or the like of the structure.
 35. Apparatus asclaimed in claim 32, wherein each anchorage is attached to a leg thatextends from the base unit.
 36. Apparatus as claimed in claim 35,wherein each anchorage is movable relative to the base unit, and suchmovement is brought about by movement of the leg relative to the baseunit.
 37. Apparatus as claimed in claim 36, wherein each leg is movablerelative to the base unit and/or adjustable in length such that thelength of that part of the leg that projects beyond the base unit isalterable.
 38. Apparatus as claimed in claim 37, wherein each leg isrotatably mounted to the base unit.
 39. Apparatus as claimed in claim38, wherein each leg is telescopically extendible and retractable. 40.Apparatus as claimed in claim 37, wherein each leg is slidably mountedwithin a housing that is fixed relative to the base unit, such thatanchorages at one end of each leg may be extended and retracted relativeto the base unit by movement of the leg relative to the housing. 41.Apparatus as claimed in claim 40, wherein the apparatus comprises fourlegs that are arranged parallel to one another.
 42. Apparatus as claimedin claim 34, wherein the operation of the anchorages is controllable bya construction worker accommodated by the base unit.
 43. Apparatus asclaimed in claim 34, wherein movement of the anchorages relative to thebase unit is controllable by a construction worker accommodated by thebase unit.
 44. Apparatus as claimed in claim 42, wherein the base unitincludes a control panel that enables a construction worker to controlsaid operation and/or movement of the anchorages.
 45. Apparatus asclaimed in claim 44, wherein the control panel includes, or is incommunication with, suitable control device.
 46. Apparatus as claimed inclaim 45, wherein the control device is a microprocessor.
 47. Apparatusas claimed in claim 44, wherein the control panel is only functionalwhen the boom and work platform are in a configuration that is suitablefor transportation of the apparatus.
 48. Apparatus as claimed in claim47, wherein the control panel includes a selector switch that must be inan appropriate state for the control panel to function.
 49. Apparatus asclaimed in claim 44, wherein each anchorage has the general form of aclamp that is arranged to captivate a beam or the like of a structure.50. Apparatus as claimed in claim 49, wherein each anchorage comprisesfirst and second clamp members that are movable relative to one anotherso as to captivate a beam or part of a beam between the clamp members onactuation of the anchorage.
 51. Apparatus as claimed in claim 50,wherein each anchorage includes a location surface that is adapted tolie against a surface of the beam, such that the beam or part of a beamis captivated between the location surface and the clamp members onactuation of the anchorage.
 52. Apparatus as claimed in claim 51,wherein each anchorage is adapted 10 for engagement with a flange of abeam comprising a pair of flanges joined by a connecting web. 53.Apparatus as claimed in claim 52, wherein the location surface isadapted to lie against an outer face of the flange, and the clamp armsare adapted to engage an inner face of the flange on either side of theconnecting web, such that the flange is captivated, in use, between thelocation surface and the first and second clamp members.
 54. Apparatusas claimed in claim 53, wherein each anchorage is fixed to one end of aleg.
 55. Apparatus as claimed in claim 54, wherein the first clampmember is mounted to a carriage, which is itself mounted within the legand includes a mechanism for moving the carriage relative to the leg,such that the first clamp member may be moved along a linear pathrelative to the leg.
 56. Apparatus as claimed in claim 55, wherein thesecond clamp member has a fixed linear position relative to the leg, andthe first and second clamp members are brought into engagement with theflange by extension of the leg until the second clamp member engages theflange, and retraction of the carriage until the first clamp memberengages the flange.
 57. A method of construction comprising: providingapparatus as claimed in any preceding claim; raising the apparatusrelative to a structure; releasably fixing the apparatus to thestructure in an elevated location relative to the ground; and moving aconstruction worker and/or construction material relative to thestructure.
 58. A method as claimed in claim 57, wherein a constructionworker is accommodated by the base unit whilst the apparatus is raisedrelative to the structure.
 59. A method as claimed in claim 58, whereinthe construction worker accommodated by the base unit is attached to thesafety rail by a safety harness during the raising of the apparatusrelative to the structure.
 60. A method as claimed in claim 57, whereinthe apparatus is raised relative to the structure by a crane.
 61. Amethod as claimed in claim 60, wherein the apparatus is fixed to thestructure in an elevated location relative to the ground while the craneremains engaged with the apparatus.
 62. A method as claimed in claim 57,wherein the apparatus is raised relative to the structure by a raisingmechanism of the apparatus that cooperates with vertical beams of thestructure.
 63. A method as claimed in claim 62, wherein operation of theraising mechanism is controlled by a construction worker accommodated bythe base unit.
 64. A method as claimed in claim 62, wherein the baseunit is fixed by the raising mechanism to the structure in an elevatedlocation relative to the ground.
 65. A method as claimed in claim 57,wherein the apparatus includes a mechanism for moving a constructionworker relative to the base unit, said mechanism comprising a workplatform that is adapted for accommodating a construction worker and amechanism for moving the work platform relative to the base unit, andthe work platform and the construction worker are elevated to a fixingsite of greater elevation relative to the ground at which theconstruction worker fixes construction material to the structure.
 66. Amethod as claimed in claim 65, wherein construction material istransported to the construction worker at the fixing site by a crane.67. A method as claimed in claim 57, wherein the apparatus comprises amechanism for moving construction material relative to the base unit,and the construction material is elevated to a fixing site of greaterelevation relative to the ground at which a construction worker fixesthe construction material to the structure.
 68. A method as claimed inclaim 67, wherein the construction material is moved using a winch.